The present invention, in some embodiments thereof, relates to cell-targeting nanoparticles comprising polynucleotide agents and uses thereof.
Most cancers are not uniform and contain subpopulations of cells that are relatively resistant to chemo/radiotherapy. These cells are not eliminated by treatment and may be the source of cancer recurrence. One leading theory is that tumors are initiated by such rare drug-resistant cells within the tumor, called cancer stem cells or tumor-initiating cells (T-IC), which share properties with normal tissue stem cells. These cells can self renew and can be passaged indefinitely both in vitro and in vivo and can differentiate into multiple cell lineages. Importantly, they are much more malignant than the bulk of tumor cells in immunodeficient mice, forming tumors with many fewer cells, and frequently the tumors are more metastatic.
One common feature of all T-IC is a high expression of CD44 named (CD44high). CD44high with or without several other markers (such as CD133, CD24low or CD24+, CD166 and EpCAM) is found in blood and solid tumors, among them breast, pancreatic, leukemia, brain and melanoma.
Most cancer stem cells are relatively drug resistant and more malignant than the bulk of tumor cells. Therefore it is imperative to develop therapies that address this subpopulation in order to treat different type of cancer stem cells successfully.
Although it is only recently that RNA interference (RNAi) was shown in mammals, the prospect of harnessing RNAi for human therapy has developed rapidly. Phase I and II clinical studies using siRNAs to treat macular degeneration and respiratory syncytial virus infection have been encouraging.
However, many of these promising therapies were performed by locally injecting siRNAs into a xenotransplanted tumor. The greatest obstacle for harnessing RNAi for cancer therapy is systemically delivering siRNAs to silence gene expression not only in a primary tumor, but also in occult metastases and disseminated disease.
Particles have been developed that systemically target leukocytes. Such particles were formed by mixing siRNAs with a fusion protein composed of a cell targeting moiety (antibody fragment or cell surface receptor ligand against an internalizing leukocyte integrin) and an RNA binding peptide such as protamine [Peer et al., Proceedings of the National Academy of Sciences of the United States of America 104, 4095-4100 (2007)]. Intravenous injection of siRNA fusion protein nanoparticles specifically target and inhibit pulmonary hematopoietic cell tumors. In addition, it has been shown that lipid-based nanoparticles decorated with anti-integrin antibody can selectively deliver siRNAs to leukocytes involved in gut inflammation [Peer et al., Science 319, 627-630 (2008)]. This platform can be used to target different cell surface receptors by changing the antibodies decorating the particle's surface. However, this is a sophisticated strategy that cannot address the ability to target cancer stem cells.
International Application WO2009/020270 and Jiang et al [Biopolymers, Vol. 89, No. 7, 2008] teach a delivery system for nucleic acids using a composition comprising polyethyleneimine and hyaluronic acid. The composition is generated at a pH above 4.5. The particles generated had a zeta potential of 3.6, 13.2 and 24.9 with a size of 21 nm.
Taetz et al. [Oligonucleotides, Vol. 19, No. 2, Epub April 2009] teaches reacting liposomes which have been previously attached to hyaluronic acid with siRNA to produce lipoplexes for the treatment of cancer. The size of the lipoplexes were between 100-200 nm with a zeta potential of about −40 mV.
Surace et al [Molecular Pharmaceutics, Vol. 6, No. 4, pages 1062-73 teaches using liposomes previously attached to hyaluronic acid to form lipoplexes together with plasmid DNA. Lipoplexes displayed a negative zeta potential and a mean diameter between 250-300 nm.
Han Su-Eun et al [Journal of Drug Targeting, Vol. 17, No. 2, February 2009] teach a delivery system for nucleic acids using a composition comprising polyethyleneimine and hyaluronic acid. The composition is generated at a pH above 4.5. The particles generated had a zeta potential between 45-70 mV and are about 185 nm in diameter.
Herringson et al [Journal of Controlled Release, Vol. 139, No. 3, pages 229-238] teaches encapsulation of siRNA into neutral stealth liposomes and engraftment with CD4 ligand. The liposomes had a mean diameter of 243 nm and a zeta potential of −11.5 mV and −1.5 mV.
Chono et al., Journal of Controlled Release, Volume 131, Issue 1, 6 Oct. 2008, Pages 64-69, teaches nanoparticle formulation comprising liposomes, protamine and hyaluronic acid for systemically delivering siRNA into a tumor.
Additional background art includes U.S. Pat. No. 7,544,374 and U.S. Patent Application No. 20090155178 which teaches non-homogeneous populations of particles of lipidated glycosaminoglycans as gene delivery materials.